/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.iotdb.flink.tsfile;

import org.apache.flink.api.common.typeinfo.TypeInformation;
import org.apache.flink.api.java.typeutils.ResultTypeQueryable;
import org.apache.flink.api.java.typeutils.RowTypeInfo;
import org.apache.flink.types.Row;
import org.apache.iotdb.tsfile.common.constant.QueryConstant;
import org.apache.iotdb.tsfile.read.common.Field;
import org.apache.iotdb.tsfile.read.common.Path;
import org.apache.iotdb.tsfile.read.common.RowRecord;

import java.util.List;
import java.util.stream.Collectors;

/**
 * The parser that parses the RowRecord objects read from TsFile into Flink Row object.
 */
public class RowRowRecordParser implements RowRecordParser<Row>, ResultTypeQueryable<Row> {

	private final int[] indexMapping;
	private final RowTypeInfo rowTypeInfo;

	public RowRowRecordParser(int[] indexMapping, RowTypeInfo rowTypeInfo) {
		this.indexMapping = indexMapping;
		this.rowTypeInfo = rowTypeInfo;
	}

	@Override
	public Row parse(RowRecord rowRecord, Row reuse) {
		List<Field> fields = rowRecord.getFields();
		for (int i = 0; i < indexMapping.length; i++) {
			if (indexMapping[i] < 0) {
				// The negative index is treated as the marker of timestamp.
				reuse.setField(i, rowRecord.getTimestamp());
			} else {
				reuse.setField(i, toSqlValue(fields.get(indexMapping[i])));
			}
		}
		return reuse;
	}

	private Object toSqlValue(Field field) {
		if (field == null) {
			return null;
		} else if (field.getDataType() == null) {
			return null;
		} else {
			switch (field.getDataType()) {
				case BOOLEAN:
					return field.getBoolV();
				case INT32:
					return field.getIntV();
				case INT64:
					return field.getLongV();
				case FLOAT:
					return field.getFloatV();
				case DOUBLE:
					return field.getDoubleV();
				case TEXT:
					return field.getStringValue();
				default:
					throw new UnsupportedOperationException(
						String.format("Unsupported type %s", field.getDataType()));
			}
		}
	}

	@Override
	public TypeInformation<Row> getProducedType() {
		return rowTypeInfo;
	}

	/**
	 * Creates RowRowRecordParser from output RowTypeInfo and selected series in the RowRecord. The row field "time"
	 * will be used to store the timestamp value. The other row fields store the values of the same field names of
	 * the RowRecord.
	 *
	 * @param outputRowTypeInfo The RowTypeInfo of the output row.
	 * @param selectedSeries The selected series in the RowRecord.
	 * @return The RowRowRecordParser.
	 */
	public static RowRowRecordParser create(RowTypeInfo outputRowTypeInfo, List<Path> selectedSeries) {
		List<String> selectedSeriesNames = selectedSeries.stream().map(Path::toString).collect(Collectors.toList());
		String[] rowFieldNames = outputRowTypeInfo.getFieldNames();
		int[] indexMapping = new int[outputRowTypeInfo.getArity()];
		for (int i = 0; i < outputRowTypeInfo.getArity(); i++) {
			if (!QueryConstant.RESERVED_TIME.equals(rowFieldNames[i])) {
				int index = selectedSeriesNames.indexOf(rowFieldNames[i]);
				if (index >= 0) {
					indexMapping[i] = index;
				} else {
					throw new IllegalArgumentException(rowFieldNames[i] + " is not found in selected series.");
				}
			} else {
				// marked as timestamp field.
				indexMapping[i] = -1;
			}
		}
		return new RowRowRecordParser(indexMapping, outputRowTypeInfo);
	}
}
